Isomerization of saturated hydrocarbons



Feb. 12, 1`946.

E. R. KANHOFER IsoMERIzATIoN oF SATURATED HYDRocARBoNs Filed July 18, 194?v sludge.

Patented Feb. 12, 1946 UNITED STATES PATENT oFFicE ISGLIERIZATION 0F SATURATED HYDROCARBONS Immer n. Kammer, chicago.' n1., assigner to Universal vOil 'Products Company, Chicago, Ill., a. corporation ofv Delaware Application. Jnlyl, 1942, Serial'No. 451,473-

ia'claims. '(ol. asu-#6835) The present invention relates to the production of isomeric hydrocarbons from saturated hydrocarbons and is primarily concerned with improvements in the method of tions. v

The production of isomeric hydrocarbons has become increasingly importantin the chemical'V and motor fuel industries, particularly'with re spect to paraiiinic hydrocarbonsv since the isomeric paraiilnsv are in general more reactive than their normal or less branched chain counterfr in general compounds of the Friedel-Crafts type will catalyze to some extentl the isomerization` re' action. These catalystsl however, besides influencing the isomerization reaction also have a' tendency to react with. the hydrocarbons to 'form undesirable hydrocarbon-catalyst commonly termed sludge. The economic feasiconducting such reaccomplexes bility of the isomerization process is dependent primarily on thcylel'd of isomeric hydrocarbons obtained per unit weight of catalyst consumed which will be controlled to'a 'large extent by the consumption of the catalyst in the formation oi tion process have been made to attempt' to in crease the yield of desired isomeric hydrocarbons per unit weight of catalyst consumed. It has been found that the addition to the reactants-ofL hydrogen halides or materials which generate hydrogen halide in situ tends to increase the ability of the Friedel-Crafts type .catalyst to influence the isomerization reaction.

alyst on a. relatively inert support or spacing agent more catalytic surface per unit weight .of

catalyst`wil1 be exposed to' the lreactants and higher Vrates of conversionmaybe obtained'.

It is an object ofthe invention to provideanimproved Amethod 1- of isomerization Ywherein rcataLVst which has been used for the isomerization of normal butane is subsequently used for the Various modiiications in the isomeriza VIt Vhas alsoI vbeen. found that by depositing the metallic halide catconversion. of hydrocarbons which isomerize more readily. In this manner the effective utilization o1 the catalyst'is substantially increased, andL as a result, the actual catalyst consumption and cost in the isomerization operation based on the. production of isomeric hydrocarbons per unit weight of catalyst is decreased.

InV one embodiment the' invention Acomprises contacting normal butane with an. isomerizationv catalyst vunder conditions regulated to form a normal butane-catalyst mixture containingy an amount. of catalyst adequate to promote subse quent isomerization, commingling the normalbutane-catalyst mixture with hydrogenhalide in a tpacked reaction zone under conditions .regulated to maintain thereactants in substantially vapor phase and tov convert a portion of. thenormal butane to isobutaneand periodicallyA interrupting the ilow of said reactants andintroducing into said reaction'zone higher boiling hydrocarbons to convert a substantial portion of the lat-- ter into isomericl hydrocarbons by the action'of the catalyst deposited on thefpackingmaterial during the previous butane isomerization step.

The invention' will be more fully describedin. the following/explanation of' the accompanying diagrammatic drawing which. illustrates in con-f ventional side elevation, one type' of apparatus in which the invention may be accomplished.

For simpiication, only those `elements whichv are essential to the explanation of the invention have been included. l

Referring to the drawing, normal butane isf introduced through line I containing valve 2 into pump 3 which discharges through line 4 containing valve 5 into heating coil 6 disposed in furnace 1. A portion of the charge stream may be directed through line 24 containing valve 25finto heating coil 26 in furnace 21 and recombinedfwith the portion 'of charging stock passing through furnace as hereinafter set forth. The tempera-i ture to which the butane passing through coil 6' is raised is dependentupon the temperature` desired in chamber I0 which will bev determined by the type of catalyst being used and the amount of hydrogen halide to be introduced ntothe ren Ther reactants` will ordinarily bel heated to a temperature high enough to comaction mixture.

'pensate for any loss in heat in the passage of the reactants through line 8. and stillmaintain a, tem.

perature of from aboutc50 to about 300 F.' and preferablybetween 1501to 210 F. inchamberl.

The hydrocarbons'. after' being -heated to thedeA 55 sired temperature,leave-furnace?! throgh'line 8 'l containing valve 9 and are directed to catalyst gf .l al

chamber Ill.

. sired products are separated from the unconverted The catalyst in chamber IU may comprise Ythe halides of aluminum, zirconium, zinc, and iron,

either alone `or admixed with one another, or

` mixed with such materials as antimony, arsenic,

bismuth and phosphorus. It will be understood that these catalysts "are not necessarily equivalent in their isomerizing activity but by the reg- 1 ulation of operating conditions to compensate for Variations in activity the novel results wherein set' forth may be obtained. Y

l It is Ordinarily desirable to maintain Y tane introduced in chambeinI in substantially `V `L15 'n i t amount of catalyst removed per unit'weight 0f 51wlnchfdischargesthrough une 33 containing Valve liquidphase. In operating vin V this manner' the hydrocarbon will be dependent upon the temperature which will control the solubility ofthe catalyst in the butane. However, this invention c is not limited to liquid phase in chamber I since l 1 a vapor or mixed phase operation maybe con ducted satisfactorily.

The Vportion of the charging stock which is .di-

` rected through furnace 21 is utilized as a heat carrying means to provide the necessary heat to raise the combined stream in line VI I- Vto the de- 1 sired isomerization conversion temperature. This heated stream leaves furnace 21 through line 28 material which may be recycled to the reaction zone. After a sufiicient amount of metallic halide catalyst has been deposited upon the support disposed within reaction zone I1, the ow of the butane-catalyst. mixture tov zoned 1 is interrupted by closing Valve I4 and ijsfdirectedto zone I8 through line I5 containing vali/'e I6. Simultaneously with the interruption of the iiow of the normal butane-catalyst mixture to zone I1, heavier saturatedvhydrocarbons, such as pentane, hexane,

heptane .or mixtures thereof or fractions of straightv run gasolines or naphthasy are introduced through line'3 0 .containing valve 3l into pump 32 ll'into'heating coil `35 in furnace 36, the hydrocontaining valve 29 and is commingled inline II with the iiuid mixture formed in chamber I0. The

entire stream in admixture with hydrogen halide introduced as hereinafter set forth .is directed through'either line I3 or line l'containing valves I4 and I6 respectively, to reaction chamber I1 or I8 respectively.

To further simplify the explanation of the drawing, it has been assumed that the normalY butane is being introduced into chamber I1 and the higher boiling hydrocarbons into chamber I8.r

'Ihe hydrogen halide activator may beintroduced through either line 50 containing valveEI or through'line 52 containing valve'53. The point y of introductionof hydrogen halide will determine, the zone in which mostA of the butane isomerization occurs. The concentrationof the hydrogen halide in the butane stream will varydepending upon the particular catalystand the operating 3 conditions selectedgbut will ordinarily be less than `40 mol percentof the butane-catalyst mixture. The heated butane-catalyst and hydrogenV halide mixture is introduced into chamber I1 whereina `substantial portion of the normal butane isconverted into isobutane. It is essential in operating `in accordance withV the invention that chamberV l I1 bemaintained under conditions such that Vthe butane is in substantially vapor phase. Therme- ,tallic halide catalyst carried in by the normal butane deposits upon the packing disposed in zone I1 forming anV active isomerizing catalyst.

.The packingin zone I1 may comprise such ma- `accordingly so thata substantial vapor phaseisl maintained.Y 'The reaction `products consisting principally of isobutane and unconverted normal butaneleave reaction zonev I 1 through line I 9 con,...

.to the desired temperature, which 'is dependent upon the'hydrocarbons being treated and the oatalyst used, but is ordinarily Awithin the range of to 600i- F. `and preferably between '150V to'250 F. The heated reactants are .directed through line 31 containing valve 38 into line 39 containing 2 valve 40 into packed reaction zone I1. These hydrocarbens contact'the active Aisomerizing catalyst whichA has previously been iormedby thedeposipressures ranging from substantially (atmospheric to about 1.000 pounds-per vsquare inch or more.

The operation may besatisfactorily conducted in y j either aliquid, mixed, or vapor phase. f Y

It has been Vfound thatVV the addition ofsmall amountsy of hydrogen tends tof-decrease the amount of undesirable side reactions which'may occur duringu the operation.' Hydrogenfupto about 20,mcll per cent of the hydrocarbon-hydrogen halide mixture may'be introduced through.

line containing valve 56, into line 51Where. it is commingled with the hydrogen halide being-intro? duced through line 54 containing Valve 49. The resulting mixture is directed through line 51into Y line31 where the mixture of hydrogen halide and (nl `terials as porcelain, pumi'ce, rebrick, quartz, ac -AV `tivated charcoal, other activated Vcarbons, di#y atomaceous earthka'olin, raw andacid-treated hydrogenis commingled witlfith'e charging stock... The reaction productsleave packedzone' QI] through line I9finto line 'IlScontaining'H valve 144 and are directed throughline 48,'to a suitable.l

fractionating system wherein the desired products are separated froml the unconvertedrnaterial j which'may be recycled to thejreaction zone I1,

The following example "illustrates .the results which' may be obtainedwhen operating in ac; j

cordance. with the invention. It isY not intended,

however, that this example shall place any undue'` f limitations on thev general broad scopof them- Vention. I

Normal 'butane along with .aboutllZ' fmolper vf' cent of HCl is heated to"1V81 E; under apressure of 25.0 pounds persquarelinch and passedthrough a bed jof granulari aluminum chloride. disposed within an insulatedA reactionchamber.; The anale.

' ysisofthe resulting reaction productsis as fol-` .Molpercent' Isobutane Y Y v40.3..Y YNormal vleuten@ Propane A Pentanes tammgyaive zu andere.directeathmugn.iinezluf The iiow of the normal butane is interrupted after about four hours processing and directed into a second reaction zone. A 59 octane number acid treated commercial hexane fraction along with mol per cent HCl heated to a temperature of 212 F. under a pressure of 500 pounds per square inch is introduced into the rst reaction zone.

The octane number of the hexane is raised from 59 to 78, an improvement of 19 octane numbers. By alternately passing the butane-catalyst mixture and the hexane through the reaction zones in the manner explained above a yield of isomerized product amounting to about 40 gallons of product per pound of aluminum chloride consumed is obtained.

I claim as my invention:

l. A continuous process for the simultaneous isomerization of normal butane and a higher boiling saturated hydrocarbon which comprises introducing a stream containing normal butane and a metallic halide isomerizing catalyst to a first reaction zone containing a solid packing material, subsequently diverting said stream from the rst zone and introducing the same to a second reaction zone containing a solid packing material, maintaining each oi" said zones at an isomerization temperature at all times and, during the introduction of said stream thereto, simultaneously isomerizing norma1 butane therein and depositing metallic halide catalyst on the packing material in each of the zones, during the diversion of said stream from the rst to the second zone introducing to the rst zone a separate stream of said higher boiling saturated hydrocarbon and isomerizing the latter in the presence of metallic halide catalyst deposited as aforesaid from the rst-named stream on the packing material in said first zone, and periodically alternating the introduction of said streams into the respective reaction zones so th'at both of the zones are in simultaneous operation with normal butane being isomerized and catalyst being deposited in one of the zones while the higher boiling saturated hydrocarbon is being isomerized in the other and each of the zones being successively employed in the isomerization of normal butane and in the l isomerization of the higher boiling saturated hydrocarbon.

2. A continuous process for the simultaneous isomerization of normal butane and a higher boiling paraffin which comprises introducing a stream containing normal butane, a hydrogen halide and a metallic halide isomerizing catalyst to a first reaction zone containing a solid packing material, subsequently diverting said stream from the first zone and introducing the same to a second reaction zone containing a solid packing material, maintaining each of said zones at an isomerization temperature at all times and, during the introduction of said stream thereto, simultaneously isomerizing normal butane therein and depositing metallic halide catalyst on the packing material in each of the zones, during the diversion of said stream from the rst to the second zone introducing to the first zone a separate stream of said higher boiling paraiiin and a hydrogen halide and isomerizing the last-named paraiiin in the presence of metallic halide catalyst deposited as aforesaid from the first-named stream on the packing material in said iirst zone, and periodically alternating the introduction of said streams into the respective reaction zones so that both of the zones arein simultaneous operation with normal butane being isomerized and catalyst being deposited in one of the zones while the higher boiling paramn is being isomerized in th'e other and each of the zones being successively employed in the isomerization of normal butane and in the isomerization of the higher boiling paraffin.

3. A continuous process for the simultaneous isomerization of normal butane and a higher boiling paraffin which comprises introducing a stream containing normal butane and an aluminum halide to a first reaction zone containing a solid packing material, subsequently ,diverting said stream from theA iirst zone and introducing the same to a second reaction zone containing a solid packing material, maintaining each of said zones at an isomerization temperature at all times and, during the introduction of said stream thereto, simultaneously isomerizing normal butane therein and depositing aluminum halide catalyst on the packing material in each of the zones, during the diversion of said stream from the first to the second zone introducing to the iirst zone a separate stream of said higher boiling paraiiin and isomerizing the latter in the presence of aluminum halide catalyst deposited as aforesaid from the iirst-named stream on the packing material in said first zone, and periodically alternating the introduction of said'streams into the respective reaction zones so that both of the zones are in simultaneous operation with normal butane being isomerized and catalyst being deposited in one of the zones while the higher boiling paraffin is being isomerized in the other and each of the zones being successively employed in the isomerization of normal butane and in the isomerization of the higher boiling paraiiin.

4. The process as dened in claim 1 further characterized in that said metallic halide comprises aluminum chloride.

5. The process as defined in claim 1 further characterized in that said separate stream containing the higher boiling saturated hydrocarbon comprises a paraiiinic gasoline fraction.

6. The process as defined in claim 1 further characterized in that a hydrogen halide is introduced to the reaction zones simultaneously with said streams.

7. The process as defined in claim 2 further characterized in that said metallic halide comprises aluminum chloride.

8. The process as defined in claim 2 further characterized in that the hydrocarbon component of said separate stream is a paraiiinic gasoline fraction.

9. The process as deiined in claim 2 further characterized in that said metallic halide and said hydrogen halide are aluminum chloride and hydrogen chloride respectively.

10. 'Ihe process as defined in claim 3 further characterized in that said separate stream comprises a gasoline fraction containing said higher boiling paraiiin.

11. Theprocess as defined in claim 3 further characterized in that the isomerization in said zones is effected in the presence of a hydrogenl 

